Wideband High-Intensity Self-Bending Bessel-Like Beam Metasurface-Based Launcher for Wireless Applications

In this article, two anisotropic holographic metasurfaces with ultralow profiles are proposed to produce wideband high-intensity self-bending Bessel-like beams with customized propagation trajectories in the microwave band. The phase distribution for generating Bessel-like beams with arbitrary paths is obtained by appropriately modifying the conical ray pattern of standard Bessel beams. Then, the phase-modulated wavefronts of Bessel-like beams are reconstructed by a holographic impedance surface with anisotropic tensor elements. A monopole is assembled on the holographic impedance surface directly without loading the complex feeding network, resulting in low-cost and low-profile characteristics. Two prototypes for generating Bessel-beams with various preset trajectories are fabricated and measured for demonstration. The measured 10 dB impedance bandwidths of two designs are 15.0–24.0 and 14.6–24.0 GHz, respectively. The longitudinal electric field intensities measured at multiple frequency points verify that the proposed holographic metasurfaces have wideband capabilities, and the resulting beam exhibits properties of high-intensity, self-bending, and self-reconstruction. The transverse electric field intensities along the propagation direction at various positions reveal that both beams achieve circularly symmetrical and apparently invariant main lobes. By extracting the coordinates of the points with the strongest field intensity on the measured reference planes, it is demonstrated that the generated beams propagate along the predetermined curved trajectories. Consequently, the proposed designs have invaluable potential in numerous fields, including secure communication, microwave power transmission, detection, and imaging.